One solution for keeping a medicament delivery device as pre-assembled as possible is to deliver the medicament delivery device with a delivery member, such as a needle, pre-attached. This solution often causes the rear end of the needle to protrude into the interior of the container, which could be a drawback if the medicament reacts with the material of the delivery member when exposed for a period of time. In that respect it would be desirable to have the rear part of the delivery member outside the container until the delivery is to be performed. To minimize the number of actions needed in order to perform an injection, some devices only need to be pressed against the injection area, without the need of injecting by pressing a button or the like, which causes the needle to penetrate the injection area and the device perform the injection. Thereby, the delivery procedure is reduced by at least one step.
A disadvantage of prior art solutions is that they sometimes are unreliable and may unintentionally be actuated. U.S. Pat. No. 6,893,420 discloses a device arranged with a locking means for locking a ledge that prevents the automatic penetration and injection means from being released before mixing of the medicament is finished. However, this device suffers from the disadvantage of a user having to remove the locking means actively from the device after the mixing is finished, thereby causing an unnecessary step which may be disadvantageous, and especially considering emergency usage of such device.
It is therefore an objection of the invention to provide a medicament delivery device that is both reliable and safe to use and that is easy to use when handling.